1. Field of the Invention
This invention relates to a zoom optical system suitable for forming an image of an object on an electronic image sensor, such as a CCD or C-MOS, and to an imaging apparatus using the zoom optical system.
2. Description of Related Art
Recently, in an electronic still camera using the electronic image sensor, such as the CCD or C-MOS, it has been required to further improve its wide angle, high variable magnification ratio, and high image quality. In particular, the demand on the high image quality has been increased with respect to a movie camera.
In the case of a lens suitable for the electronic image sensor such as the CCD or C-MOS, it is required that the exit pupil is relatively spaced away from the image plane. This requirement does not generally constitute an obstacle even though other elements corresponding to image sensors (for example, a silver-halide film and the like) are used.
Such problems have been discussed by proposals such as those disclosed, for example, in Japanese Patent Kokai Nos. 2001-242379, 2003-315676, 2002-72087, and 2002-62478.